The present invention relates to the mechanical harvesting of ground crops. More particularly, the invention provides an adjustment mechanism for altering the distance setting between centers of at least one pair of driven revolving pairs (such as helixes) on site as needed to suit changing conditions encountered during harvesting.
Harvesting machines for ground row crops have been developed to meet the needs of farmers who no longer have available a dependable supply of low-wage seasonal workers. The required qualities of a harvesting machine are to gather a high percentage of fruit/vegetables from ground plants, while at the same time minimizing damage to the produce and minimizing damage to and collection of part of the plant. Collecting of 80% of the vegetable (fruit) under cultivation is considered acceptable machine performance. The remaining crop is later collected by hand.
Many machines are provided with a conveyor for receiving cut crops from the revolving pairs and for transferring the crops to an on-board storage bin. A control cab is supported on a framework seating an operator. The cab has transparent panels enabling a human operator to view the harvesting process. This operator may or may not be the vehicle driver. A plurality of wheels support the framework above ground level and allow the harvesting to advance, either under its own power or as drawn by a tractor.
Although agricultural harvesting machines have been in use for several decades, and the general design of such machines has been stabilized, a search of US patents failed to produce any reference relevant to the improvement disclosed in the present invention. The majority of prior art references to harvesters which were reviewed, such as U.S. Pat. Nos. 5,359,836, 5,437,145 5,535,578 7,303,058 and 7,404,283, US Patent Application Publication No. 2006/0196161, and EP 640 277 A1, are concerned with keeping the harvester head at a suitable height and angle relative to the ground being traversed.
As part of an effort to improve harvesting efficiency, in general, and harvesting of paprika in particular, the present inventor has determined by extensive tests that the ability to apply pressure on the plant by adjusting the spacing between centers of the rotating means specifically of a helix pair during the harvesting operation would make possible a significant increase of the percentage of crop gathered by the machine in a single pass. This innovation was not found in prior art devices, and is not taught or suggested in any of the above-listed documents. Such adjustment would apparently lead to serious mechanical complication of the helix bearings and drive mechanism. In addition to these considerations, existing designs failed to provide sufficient flexibility of the helix bearing support, although this is needed in order to reduce the percentage of damaged crop.
In all known machines, the adjustment, if possible, is done manually prior to the harvesting and cannot be done during the harvesting operation.